There is frequently a need to be able to turn a workpiece such as a pipe or a pulley for repairs, replacement and other services. Standard wrenches do not fit these workpieces and often the workpiece is so situated that access to the workpiece is very difficult. In these situations a flexible strap and a means for tightening the strap around the workpiece is essential.
A specialized form of a strap wrench is an oil filter wrench which are disclosed in U.S. Letters Patent Nos. 3,465,622 issued to Winans, 4,114,481 issued to Kowalczyk and 4,506,568 issued to Aamodt. Both Winans and Kowalczyk disclose a clamping band with a center opening and the ends of the bands connected to pivot points. While being useful in removing oil filters, these devices have pivoting points which are subject to damage and further are substantially closed loops which can be used only with workpieces which are accessible from one end so that the loop can be slid over the workpiece. Aamodt discloses the ends of a strap passing through a longitudinal slot in each part of a two part cylindrical holder and overcomes the problems presented by Winans and Kowalczyk. However, the device of Aamodt comprises two separate holder pieces which must be placed one within the other. This is not easily accomplished in restricted work space. Further, loss or misplacement of one of the holder pieces renders the device useless.
A chain wrench is disclosed in U.S. Letters Patent No. 2,353,642 issued to Buice. U.S. Letters Patent No. 4,160,394 issued to Crumpacker discloses a wrench having an elongated handle received on a bracket and a flexible loop connected to the handle. Adjustment means is provided by manipulation of a sleeve surrounding a rigid inner handle section. U.S. Letters Patent No. 3,373,637 issued to Behnke discloses a portable rotary drive unit having a rotary drive socket with a peripheral ring gear driven by a motor. These comparatively complex devices are expensive, relatively heavy, and are not conducive to work in confined spaces. U.S. Letters Patent No. 1,911,815 issued to Deringer et al disclose a strap wrench in which one end of the strap is attached to an elongated handle and the other end of the strap passes through several inclines and slots in the handle to secure the strap. Operation of this device is also restricted when working in a confined space. U.S. Letters Patent No. 3,962,936 issued to Lewis discloses a strap wrench having loose ends mounted in a cylinder having a slot passing diametrically through the center. The slot receives both ends of the strap and the cylinder is rotated, wrapping the strap around the cylinder to produce a tightening action. Although this device has been known since 1976, it has not had public acceptance and the applicant is unaware of any of these devices being available on the open market.
U.S. Letters Patent No. 701,489 issued to Love discloses a pipe wrench wherein one end of the strap is attached to a handle, the strap passing through a slot in the handle, around the workpiece over a nose on the handle, and back through the same slot in the handle. U.S. Letters Patent No. 1,478,110 issued to Ellison also discloses a handle having a nose thereon over which the strap passes as the strap enwraps the workpiece. The handle further has two laterally extending arms and a bridge portion in which the strap is received. U.S. Letters Patent No. 2,186,430 issued to Richter discloses a household implement having a handle with a slot therein. One end of a strap is attached to the handle, the strap passing through the slot, around the workpiece and returning through the slot. U.S. Letters Patent No. 2,458,393 issued to Loudfoot discloses a handle having three aligned openings and a frictional cord having both ends attached to the handle. The frictional cord is threaded through openings to form a loop to engage the workpiece. U.S. Letters Patent No. 2,995,965 issued to Hockney discloses a strap having one end folded about a pin and secured to the body of the strap. The other end of the strap is looped about the workpiece and threaded through an elongated slot in a cylindrical retainer body. The retainer body has ends which may engage a handle member to rotate the retainer body to secure the strap about the workpiece.
None of the above have provided a simple, easy to operate, inexpensive lightweight strap wrench which can be used in confined spaces where access is difficult and a need for such a wrench exists.